Stable Formamidinium-Based Centimeter Long Two-Dimensional Lead Halide Perovskite Single-Crystal for Long-Life Optoelectronic Applications

摘要

Solution-processable 2D metal-halide perovskites are highly promising for cost-effective optoelectronic applications due to their intrinsic multiquantum well structure. However, the lack of stability is still a major obstacle in the use of this class of materials in practical devices. Here, the authors demonstrate the stable optoelectronic properties using formamidinium (FA)-based centimeter-long 2D perovskite (BA)(2)FAPb(2)I(7) high-quality single-crystal controlled by the thickness of two perovskite layers. The large area single-crystal exhibits good crystallinity, phase purity, and spectral uniformity. Moreover, the (BA)(2)FAPb(2)I(7) single-crystal shows excellent stability at open atmospheric conditions when compared to methylammonium (MA)-based (BA)(2)MAPb(2)I(7) counterparts. The photodetectors fabricated using 2D perovskite single-crystal on the rigid Si/SiO2 substrate reveal high photoresponsivity (R-lambda)(approximate to 5 A W-1), the fast response time (20 ms), specific detectivity (D*) (approximate to 3.5 x 10(11) Jones), and excellent durability under 488 nm laser illumination. The R-lambda and D* values are obtained from the (BA)(2)FAPb(2)I(7) single-crystal 25 times and three orders magnitudes, respectively, higher than the (BA)(2)MAPb(2)I(7) single-crystal. Additionally, the perovskite material on flexible polymer substrate reveals good photo-sensing properties in both bending and nonbending states.